The owner of a Westchester County garbage-hauling company was sentenced yesterday to 33 months in prison for tax fraud conspiracy.

Thomas Milo, the owner of Suburban Carting Corporation, was also ordered in Federal District Court in Manhattan to pay a total of $3 million in restitution to the Internal Revenue Service and to Westchester County.

Mr. Milo, 60, of Pelham, was ordered to surrender to the authorities by April 23 to begin serving his sentence. He is the first of 21 defendants to be sentenced in the case.

According to court papers, Mr. Milo and his accomplices stifled competition from other companies by unlawfully asserting under a ''property rights system'' that they owned a permanent right to every location or stop where several of their affiliated companies picked up garbage.

The companies included Suburban Carting and Trottown Transfer, which Mr. Milo also controlled.

Prosecutors contended that the property rights system was perpetuated as a result of Mr. Milo's affiliation with, and decades-long support from, members and associates of the Genovese and Gambino organized crime families.

United States Attorney Mary Jo White praised the efforts of Federal investigators ''to wipe out the influence of organized crime -- and those who seek its backing -- from the waste-hauling industry and other industries where competition has been stifled.''